Publications

genetic conflict and conditional altruism in social aphid colonies.	although kin selection is central to the modern study of social evolution, recent studies of social species have revealed that no simple relationship exists between levels of kinship and sociality. the soldier-producing aphids are unique among highly social animals because, barring movement by aphids between colonies, they occur in clonal groups of genetically identical individuals. potentially, clonality simplifies efforts to understand social evolution in aphids by obviating issues of intragro ...	2001	11562469
individual and population variation in invertebrates revealed by inter-simple sequence repeats (issrs).	pcr-based molecular markers are well suited for questions requiring large scale surveys of plant and animal populations. inter-simple sequence repeats or issrs are analyzed by a recently developed technique based on the amplification of the regions between inverse-oriented microsatellite loci with oligonucleotides anchored in microsatellites themselves. issrs have shown much promise for the study of the population biology of plants, but have not yet been explored for similar studies of animals. ...	2001	15455068
extremely low levels of genetic polymorphism in endosymbionts (buchnera) of aphids (pemphigus).	molecular evolutionary studies have suggested that vertically transmitted endosymbionts are subject to accumulation of deleterious mutations through genetic drift. predictions of this hypothesis for patterns of intraspecific polymorphism were borne out in the single relevant study available, on the symbiont buchnera aphidicola of uroleucon ambrosiae. in order to examine the generality of this result, we surveyed dna sequence variation in buchnera of the distantly related aphid, pemphigus obesiny ...	2002	12453247
kin structure provides no explanation for intruders in social aphids.	nontraditional social organisms have received increasing attention in recent years, because they present opportunities to study the convergent properties of social evolution. some aphid species are social, occurring in dense clones with specialized morphs that attack predators and parasites. little is known about how social aphid colonies resolve conflicts of interest when clonal barriers break down. pemphigus obesinymphae is a north american gall-forming social aphid that produces both nymphal ...	2007	17845438
the cost of conflict in aphid societies.	most social aphids are found within plant galls, inside of which clonally-derived family groups feed, and specialized larval castes forego reproduction and perform various cooperative tasks, including group defence. when unrelated aphids move between clones, conditions are ripe for conflict because galls and cooperative defence are shared resources that are vulnerable to exploitation. a key unknown is whether conflict is costly in aphid social groups. we show that diversity within groups is nega ...	2010	19912452
an alternative pathway to eusociality: exploring the molecular and functional basis of fortress defense.	some animals express a form of eusociality known as "fortress defense," in which defense rather than brood care is the primary social act. aphids are small plant-feeding insects, but like termites, some species express division of labor and castes of aggressive juvenile "soldiers." what is the functional basis of fortress defense eusociality in aphids? previous work showed that the acquisition of venoms might be a key innovation in aphid social evolution. we show that the lethality of aphid sold ...	2017	28608545